Types of Truth
Arithmetical Truths
When we say that 3 + 4 = 7, we are making a claim about an arithmetical truth. This truth can also be expressed in ordinary language:three things added to three things gives us seven things.
Arithmetical truths are often expressed in the abstract, as with the equation above, but there is normally a background of reality. This type of simple truths are among the most certain truths we have.
Geometrical Truths
geometrical truths are statements about spatial relationships. As with arithmetical truths, these can also be expressed as abstractions (for example the Pythagorean Theorem) or in ordinary language (the sum of the inside angles of a square is 360 degrees). And, as with arithmetical truths, geometrical truths are also among the most certain truths we can have.
Logical Truths (Analytic Truths)
Also sometimes referred to as analytic truths, logical truths are statements that are true simply by definition of the terms that are used. The label "analytic truth" is derived from the idea that we can tell that the statement is true just by analyzing the words being used — if we understand the statement, then we must also know that it is true. An example of this would be "no bachelors are married" — if we know what "bachelor" and "married" mean, then we know for a fact that the statement is accurate.
At least, that is the case when logical truths are expressed in ordinary language. Such statements can also be expressed more abstractly as with symbolic logic — in those cases, the determination of whether a statement is true or not will be very similar to making such a determination of an arithmetic equation. For example: A=B, B=C, therefore A=C.
Synthetic Truths
Much more common and interesting are synthetic truths: these are statements which we cannot know as true simply by virtue of doing some mathematical calculations or an analysis of the meanings of words. When we read a synthetic statement, the predicate is offered as adding new information not already contained in the subject.
Thus, for example, "men are tall" is a synthetic statement because the concept "tall" is not already a part of "men." It is possible for the statement to be either true or false — if true, then it's a synthetic truth. Such truths are more interesting because they teach us something new about the world around us — something we didn't know before. The risk, however, is that we might be wrong.
Ethical Truths
The case of ethical truths is somewhat unusual because it isn't at all clear that such a thing even exists. It is certainly the case that many people believe in the existence of ethical truths, but that is a hotly disputed subject in moral philosophy. At the very least, even if ethical truths exist, it isn't at all clear how we can come to know them with any degree of certainty.
Unlike other statements of truth, ethical statements are expressed in a normative manner. We say that 7 + 2 = 9, not 7 + 2 should equal 9. We say that "bachelors are not married" rather than "it is immoral for bachelors to be married." Another feature of ethical statements is that they tend to express something about the way the world could be, not the way the world currently is. Thus, even if ethical statements could qualify as truths, they are very unusual truths indeed.
• Correspondence Theory of Truth: This theory states that a statement (a “proposition”) is true if it corresponds to (or reflects) reality. If somebody states “It is raining” (the proposition) then it is true only if it is really raining outside (reality). The interesting question is now: “What is reality”? We know that senses can deceive us. So how is reality really like? And of course we have to assume that something like reality really does exist and is not simply a product of our mind.
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• Coherence Theory of Truth: This theory states that a statement (a proposition) is true if it is consistent with other things that are considered true (and do not contradict it). Whether the statement reflects reality or not is not of primary importance. A proposition is true if it “fits into the system”. For example, I hear a pencil falling to the ground. A second person in the room also hears it, and the pencil that I just saw on my table a moment ago is now gone. Three observations fit together: me hearing it, a second person hearing it and the missing pencil. According to the coherence theory, the proposition “the pencil hit the ground” is true. But did the pencil really fall to the ground or can something else explain these observations? This is of course a different question.
• The Pragmatic Theory of Truth: This theory states that something is true if it is useful. Whether or not it reflects reality is of minor importance. Somebody (person A) may, for example, believe that earning much money is the most important thing in one’s life. This belief is true for this person and it is indeed a very useful belief. The person’s actions will be guided by this belief. The statement “Earning much money is important” is true for this person. Person B has a different view. B thinks that money is of minor importance. B thinks that having many friends is the most important thing. And guess what! This belief too is very useful! It is true for person B. His or her actions will be guided by it.